diff --git a/SConstruct b/SConstruct
index cddcf61f1..a86566ce1 100644
--- a/SConstruct
+++ b/SConstruct
@@ -1736,11 +1736,14 @@ if not preconfigured:
         # c++11 support / https://github.com/mapnik/mapnik/issues/1683
         #  - upgrade to PHOENIX_V3 since that is needed for c++11 compile
         env.Append(CPPDEFINES = '-DBOOST_SPIRIT_USE_PHOENIX_V3=1')
-        #  - workaround boost gil channel_algorithm.hpp narrowing error
-        # TODO - remove when building against >= 1.55
-        # https://github.com/mapnik/mapnik/issues/1970
         if 'clang++' in env['CXX']:
+            env.Append(CXXFLAGS = '-Wno-unknown-pragmas')
+            #  - workaround boost gil channel_algorithm.hpp narrowing error
+            # TODO - remove when building against >= 1.55
+            # https://github.com/mapnik/mapnik/issues/1970
             env.Append(CXXFLAGS = '-Wno-c++11-narrowing')
+        if 'g++' in env['CXX']:
+            env.Append(CXXFLAGS = '-Wno-pragmas')
 
         # Enable logging in debug mode (always) and release mode (when specified)
         if env['DEFAULT_LOG_SEVERITY']:
@@ -1781,14 +1784,14 @@ if not preconfigured:
 
         # Common flags for g++/clang++ CXX compiler.
         # TODO: clean up code more to make -Wsign-conversion -Wconversion -Wshadow viable
-        common_cxx_flags = '-Wall -Wsign-compare %s %s -ftemplate-depth-300 ' % (env['WARNING_CXXFLAGS'], pthread)
+        common_cxx_flags = '-Wall -Wsign-compare -Wextra %s %s -ftemplate-depth-300 ' % (env['WARNING_CXXFLAGS'], pthread)
 
         if env['DEBUG']:
-            env.Append(CXXFLAGS = common_cxx_flags + '-O0 -fno-inline')
+            env.Append(CXXFLAGS = common_cxx_flags + '-O0')
         else:
             # TODO - add back -fvisibility-inlines-hidden
             # https://github.com/mapnik/mapnik/issues/1863
-            env.Append(CXXFLAGS = common_cxx_flags + '-O%s -Wextra -Wno-unknown-pragmas' % (env['OPTIMIZATION']))
+            env.Append(CXXFLAGS = common_cxx_flags + '-O%s' % (env['OPTIMIZATION']))
         if env['DEBUG_UNDEFINED']:
             env.Append(CXXFLAGS = '-fsanitize=undefined-trap -fsanitize-undefined-trap-on-error -ftrapv -fwrapv')
 
diff --git a/benchmark/test_rendering_shared_map.cpp b/benchmark/test_rendering_shared_map.cpp
index d78d8a1d4..3f98f7f3a 100644
--- a/benchmark/test_rendering_shared_map.cpp
+++ b/benchmark/test_rendering_shared_map.cpp
@@ -17,8 +17,7 @@ template <typename Renderer> void process_layers(Renderer & ren,
                                             mapnik::request const& m_req,
                                             mapnik::projection const& map_proj,
                                             std::vector<mapnik::layer> const& layers,
-                                            double scale_denom,
-                                            mapnik::box2d<double> const& map_extent)
+                                            double scale_denom)
 {
     unsigned layers_size = layers.size();
     for (unsigned i=0; i < layers_size; ++i)
@@ -100,7 +99,7 @@ public:
         mapnik::agg_renderer<mapnik::image_32> ren(*m_,m_req,variables,im,scale_factor_);
         ren.start_map_processing(*m_);
         std::vector<mapnik::layer> const& layers = m_->layers();
-        process_layers(ren,m_req,map_proj,layers,scale_denom,extent_);
+        process_layers(ren,m_req,map_proj,layers,scale_denom);
         ren.end_map_processing(*m_);
         if (!preview_.empty()) {
             std::clog << "preview available at " << preview_ << "\n";
@@ -124,7 +123,7 @@ public:
                 mapnik::agg_renderer<mapnik::image_32> ren(*m_,m_req,variables,im,scale_factor_);
                 ren.start_map_processing(*m_);
                 std::vector<mapnik::layer> const& layers = m_->layers();
-                process_layers(ren,m_req,map_proj,layers,scale_denom,extent_);
+                process_layers(ren,m_req,map_proj,layers,scale_denom);
                 ren.end_map_processing(*m_);
             }            
         }
diff --git a/include/mapnik/simplify_converter.hpp b/include/mapnik/simplify_converter.hpp
index 5fa53b815..c6c2d73c5 100644
--- a/include/mapnik/simplify_converter.hpp
+++ b/include/mapnik/simplify_converter.hpp
@@ -194,6 +194,9 @@ private:
         return previous_vertex_.cmd;
     }
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunknown-pragmas"
+#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
     unsigned output_vertex_distance(double* x, double* y) {
         if (status_ == closing) {
             status_ = end;
@@ -237,6 +240,7 @@ private:
         *y = vtx.y;
         return vtx.cmd;
     }
+#pragma GCC diagnostic pop
 
     template <typename Iterator>
     bool fit_sleeve(Iterator itr,Iterator end, vertex2d const& v)
diff --git a/plugins/input/shape/shape_index_featureset.cpp b/plugins/input/shape/shape_index_featureset.cpp
index 20ccdff23..2ff18cd9f 100644
--- a/plugins/input/shape/shape_index_featureset.cpp
+++ b/plugins/input/shape/shape_index_featureset.cpp
@@ -28,10 +28,14 @@
 #include <mapnik/feature_factory.hpp>
 
 // boost
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #include <boost/algorithm/string.hpp>
 #ifdef SHAPE_MEMORY_MAPPED_FILE
 #include <boost/interprocess/streams/bufferstream.hpp>
 #endif
+#pragma GCC diagnostic pop
 
 #include "shape_index_featureset.hpp"
 #include "shape_utils.hpp"
diff --git a/src/marker_cache.cpp b/src/marker_cache.cpp
index f64ae152e..024be9c27 100644
--- a/src/marker_cache.cpp
+++ b/src/marker_cache.cpp
@@ -34,8 +34,12 @@
 #include <mapnik/util/fs.hpp>
 
 // boost
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #include <boost/assert.hpp>
 #include <boost/algorithm/string.hpp>
+#pragma GCC diagnostic pop
 
 // agg
 #include "agg_rendering_buffer.h"
diff --git a/src/symbolizer_keys.cpp b/src/symbolizer_keys.cpp
index 832e4d173..bc81756ec 100644
--- a/src/symbolizer_keys.cpp
+++ b/src/symbolizer_keys.cpp
@@ -25,7 +25,11 @@
 #include <mapnik/simplify.hpp>
 
 // boost
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #include <boost/algorithm/string/replace.hpp>  // for replace
+#pragma GCC diagnostic pop
 
 namespace mapnik {